↔️ 百分比差异计算器Percentage Difference Calculator

使用说明与常见问题How-to & FAQ

「百分比差异计算器」是什么？What is the Percentage Difference Calculator tool?

计算两个数之间的百分比差异：|A − B| ÷ ((A + B) ÷ 2) × 100%，并分别给出从 A 到 B、从 B 到 A 的百分比变化，避免混淆两者。Find the percentage difference between two values, |A − B| ÷ ((A + B) ÷ 2) × 100%, alongside the percentage change from A to B and from B to A so the two are not confused.

如何使用「百分比差异计算器」？How do I use the Percentage Difference Calculator tool?

在「百分比差异计算器」中，填写「数值 A」、「数值 B」等参数，结果会随输入实时计算并显示在下方。In the Percentage Difference Calculator: Fill in "Value A", "Value B"; results are recalculated instantly as you type.

百分比差异和百分比变化有什么区别？Percentage difference vs percentage change?

百分比变化有方向，以原值为基准：(新 − 旧) ÷ 旧；百分比差异没有方向，以两数平均值为基准，适合比较两个地位相同的数（如两家店的价格）。Percentage change has a direction and uses the original as the base: (new − old) ÷ old. Percentage difference has no direction and uses the average of the two — suited to comparing two peers, like prices at two shops.

为什么 40→50 是 +25%，50→40 是 −20%？Why is 40→50 +25% but 50→40 −20%?

因为基准不同：前者以 40 为基准，后者以 50 为基准。百分比差异以平均值 45 为基准，两个方向都是 22.22%。Because the base differs: 40 in one case, 50 in the other. The percentage difference uses the average, 45, so it is 22.22% either way.

计算精度如何？How precise are the results?

「百分比差异计算器」使用 JavaScript 双精度浮点数（约 15–16 位有效数字）；极大或极小的数值可能存在精度误差。The Percentage Difference Calculator uses double-precision floating point (about 15–16 significant digits); very large or very small values may lose precision.

「百分比差异计算器」免费吗？需要注册吗？Is the Percentage Difference Calculator free? Do I need an account?

「百分比差异计算器」完全免费，无需注册或安装，打开网页即可使用，手机和电脑都能用；输入的内容只在你的浏览器本地处理。The Percentage Difference Calculator is completely free with no sign-up or install and works on phones and desktops; what you enter is processed only in your browser.